Computer Programs

NAME OR DESIGNATION OF PROGRAM, COMPUTER, DESCRIPTION OF PROBLEM OR FUNCTION, METHOD OF SOLUTION, RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM, TYPICAL RUNNING TIME, UNUSUAL FEATURES OF THE PROGRAM, RELATED AND AUXILIARY PROGRAMS, STATUS, REFERENCES, MACHINE REQUIREMENTS, LANGUAGE, OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED, OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS, NAME AND ESTABLISHMENT OF AUTHOR, MATERIAL, CATEGORIES

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To submit a request, click below on the link of the version you wish to order. Rules for end-users are
available here.

Program name | Package id | Status | Status date |
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ANCON | NESC0486/01 | Tested | 01-APR-1975 |

ANCON | NESC0486/02 | Tested | 01-MAR-1975 |

Machines used:

Package ID | Orig. computer | Test computer |
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NESC0486/01 | CDC 6600 | CDC 6600 |

NESC0486/02 | IBM 370 series | IBM 370 series |

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3. DESCRIPTION OF PROBLEM OR FUNCTION

ANCON solves the point-reactor kinetic equations including thermal feedback. Lump-type heat balance equations are used to represent the thermodynamics, and the heat capacity of each lump can vary with temperature. Thermal feedback can be either a linear or a non-linear function of lump temperature, and the impressed reactivity can be either a polynomial or sinusoidal function.

ANCON solves the point-reactor kinetic equations including thermal feedback. Lump-type heat balance equations are used to represent the thermodynamics, and the heat capacity of each lump can vary with temperature. Thermal feedback can be either a linear or a non-linear function of lump temperature, and the impressed reactivity can be either a polynomial or sinusoidal function.

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4. METHOD OF SOLUTION

In ANCON the system of coupled first-order differential equations is solved by a method based on continuous analytic continuation (references 2 and 3). The basic procedure consists of expanding all the dependent variables except reactivity in Taylor series, with a truncation error criterion, over successive intervals on the time axis. Variations of the basic procedure are used to increase the efficiency of the method in special situations. Automatic switching from the basic procedure to one of its variations (and vice-versa) may occur during the course of a transient. The method yields an analytic criterion for the magnitude of the time-step at any point in the transient.

In ANCON the system of coupled first-order differential equations is solved by a method based on continuous analytic continuation (references 2 and 3). The basic procedure consists of expanding all the dependent variables except reactivity in Taylor series, with a truncation error criterion, over successive intervals on the time axis. Variations of the basic procedure are used to increase the efficiency of the method in special situations. Automatic switching from the basic procedure to one of its variations (and vice-versa) may occur during the course of a transient. The method yields an analytic criterion for the magnitude of the time-step at any point in the transient.

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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The program is currently restricted to a maximum of six delayed neutron groups and a maximum of 56 lumps. Larger problems can be accommodated on a 65K computer by increasing the dimensions of a few subscripted variables. Also, the code is currently restricted to a constant external transport delays, only the open-loop response of a reactor can be computed with ANCON.

The program is currently restricted to a maximum of six delayed neutron groups and a maximum of 56 lumps. Larger problems can be accommodated on a 65K computer by increasing the dimensions of a few subscripted variables. Also, the code is currently restricted to a constant external transport delays, only the open-loop response of a reactor can be computed with ANCON.

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6. TYPICAL RUNNING TIME

Running time is highly problem-dependent, depending on such factors as the number of equations in the system, the feedback and heat balance options used, the time at which the transient is terminated, and whether the transient is slow or fast. Most problems that have been run with ANCON required 1 to 10 minutes on the CDC 6600. NESC executed the sample problem in 30 CPU seconds on an IBM 3033.

Running time is highly problem-dependent, depending on such factors as the number of equations in the system, the feedback and heat balance options used, the time at which the transient is terminated, and whether the transient is slow or fast. Most problems that have been run with ANCON required 1 to 10 minutes on the CDC 6600. NESC executed the sample problem in 30 CPU seconds on an IBM 3033.

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7. UNUSUAL FEATURES OF THE PROGRAM

The most important characteristic of the computational method is that it yields an analytic criterion for the magnitude of the time-step. This criterion is such that the time-step automatically expands or contracts, depending on the behavior of the dependent variables within each interval. The use of this criterion quarantees that the accumulated fractional error in each dependent variable is always less than N*E, where N is the number of time-steps and E is an input truncation error parameter.

Also, the code is structured in a form such that reactivity, heat balance, and source options other than those presently available can be incorporated with a minimum of code modification.

The most important characteristic of the computational method is that it yields an analytic criterion for the magnitude of the time-step. This criterion is such that the time-step automatically expands or contracts, depending on the behavior of the dependent variables within each interval. The use of this criterion quarantees that the accumulated fractional error in each dependent variable is always less than N*E, where N is the number of time-steps and E is an input truncation error parameter.

Also, the code is structured in a form such that reactivity, heat balance, and source options other than those presently available can be incorporated with a minimum of code modification.

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8. RELATED AND AUXILIARY PROGRAMS

The ANCON output is printed but not plotted because plotting codes are frequently system-dependent. However, the output is saved on logical unit TAPE1, which may be either a tape unit or a disk file. From TAPE1, the user can make plots with his own plotting routines. The original IBM 360 conversion was by P. Henline of the National Energy Software Center.

The ANCON output is printed but not plotted because plotting codes are frequently system-dependent. However, the output is saved on logical unit TAPE1, which may be either a tape unit or a disk file. From TAPE1, the user can make plots with his own plotting routines. The original IBM 360 conversion was by P. Henline of the National Energy Software Center.

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Package ID | Status date | Status |
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NESC0486/01 | 01-APR-1975 | Tested at NEADB |

NESC0486/02 | 01-MAR-1975 | Tested at NEADB |

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10. REFERENCES

- J.C. Vigil,

Solution of the Nonlinear Reactor Kinetics Equations by Continuous Analytic Continuation,

LA-3518, May 1, 1966.

- J.C. Vigil,

Solution of the Reactor Kinetics Equations by Analytic

Continuation

Nuclear Science and Engineering, Vol. 29, pp. 392-401, 1967.

- J.C. Vigil,

Solution of the Nonlinear Reactor Kinetics Equations by Continuous Analytic Continuation,

LA-3518, May 1, 1966.

- J.C. Vigil,

Solution of the Reactor Kinetics Equations by Analytic

Continuation

Nuclear Science and Engineering, Vol. 29, pp. 392-401, 1967.

NESC0486/01, included references:

- J.C. Vigil:ANCON - User's Manual

LA-4616 (May 1971).

NESC0486/02, included references:

- J.C. Vigil:ANCON - User's Manual LA-4616 (May 1971).

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11. MACHINE REQUIREMENTS

ANCON requires 32K words of central memory, one peripheral storage device (logical unit 1), card reader (logical unit 10), print (logical unit 9), and card punch. Standard system- library functions and a CLOCK routine are used. The CLOCK routine is not essential. A dummy CLOCK routine is provided with the IBM 360 version package.

ANCON requires 32K words of central memory, one peripheral storage device (logical unit 1), card reader (logical unit 10), print (logical unit 9), and card punch. Standard system- library functions and a CLOCK routine are used. The CLOCK routine is not essential. A dummy CLOCK routine is provided with the IBM 360 version package.

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Package ID | Computer language |
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NESC0486/01 | FORTRAN-IV |

NESC0486/02 | FORTRAN-IV |

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NESC0486/01

File name | File description | Records |
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NESC0486_01.001 | SOURCE PROGRAM (F4) | 2175 |

NESC0486_01.002 | SAMPLE CASE INPUT DATA | 36 |

NESC0486_01.003 | SAMPLE CASE PUNCHED OUTPUT | 15 |

NESC0486_01.004 | SAMPLE CASE PRINTED OUTPUT | 734 |

NESC0486/02

File name | File description | Records |
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NESC0486_02.001 | SOURCE PROGRAM (F4) | 2191 |

NESC0486_02.002 | SAMPLE PROBLEM INPUT DATA | 36 |

NESC0486_02.003 | JCL | 3 |

NESC0486_02.004 | SAMPLE PROBLEM PRINTED OUTPUT | 698 |

Keywords: delayed neutrons, reactivity, reactor kinetics, temperature feedback.